2 Serial Devices on one board

Hi,

I didn't get a chance to look at the data sheets yesterday ... your comment about RS232 threw me off on the wrong track ...

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I am currently working on a project in which I need to connect two digital sensors, a Temp & Humidity sensor(SHT 15) and an accelerometer (ADXL345) both digital sensors. They also both use serial communications

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The ADXL345 can be accessed via either SPI or I2C, so the device can be connected directly to pins on the expansion header. The DE0-nano contains the ADXL345 device, so there should be examples you can use with that board.

The SHT15 sensor

http://www.sparkfun.com/datasheets/sensors/sht1x_datasheet.pdf

uses a non-standard serial protocol, which uses a serial clock and bidirectional serial data, where the data signal should only ever be driven low to avoid driver conflict. You will have to create a custom interface to this device, I'd recommend starting with bit-banged I/O, where the clock signal is driven as an output and the data controls the enable on a tri-state buffer that will drive low when enabled.

Both of these devices can be interfaced directly to your FPGA pins. You would not use an RS232 level translator.

Try coding up an interface, and if you have trouble, ask questions here on the forum.

Cheers,

Dave